This invention relates to fuel compositions having improved low temperature characteristics. More particularly this invention relates to compositions comprising distillate hydrocarbon fuels having minor amounts of heavy metal salts of certain branched chain carboxylic acids.
As is well known to those skilled in the art, diesel fuels present problems at low temperatures because of poor flow characteristics and clogging of fuel filters. Consequently there is a continuing need for more efficient means for solving these low temperature problems. The materials described herein are metal salts of specific monocarboxylic acids which when added to a diesel fuel significantly improve its filterability, cloud point and pour point.
European Patent Application No. 79200612.4, (Publication No. 010 807 Al) filed on Oct. 25, 1979, discloses derivatives of branched chain monocarboxylic acids. These are amides of ammonia and aliphatic or aromatic amines having at least 1 to 15 primary or secondary amino groups, or salts of alkali metals or alkaline earth metals. The anion of these derivatives is a branched chain monocarboxylic acid moiety commonly known as a telomer acid.
U.S. Pat. No. 4,283,314 discloses resin compositions having improved lubricating properties which employ branched chain high molecular weight ester derivatives of monocarboxylic acids. These monocarboxylic acids can be of the telomer acid type.
The telomer acids described in the aforementioned European Patent Application Publication No. 0 010 807 Al (AKZO CHEMIE) are commercially available through Akona, Inc., Asheville, N.C. European Patent Application Publication No. 0 010 807 Al and U.S. Pat. No. 4,283,314 are incorporated herein in their entirety by reference.
Additives effective in lubricating oils are not necessarily effective in distillate fuels. See Table 1, Example 1, a commercial telomer acid calcium salt (average side chain length or acid about C.sub.14) made by Akzo Chemie shows no effect on any of the properties.
It is known that additives which affect pour point cannot be presumed to affect other low temperature properties such as cloud point or filterability, see commercial additive data (Example 3) of Table 1.
The characteristics of telomer acids and their derivatives have been widely explored by Akzo Chemie. Outstanding properties in the areas of clarity, lubricity, rheology, thermo-oxidative and UV stability have been found. The chemical and physical properties of telomer acids and their derivatives suggest advantages for their application in diverse areas such as polymer additives, metal lubricant additives, spin finishes, metal ion extraction complexing aids, printing inks, surface active formulations, coatings, hot melts, greases, specialty plasticisers and water repellants. But there is no prior art known to applicant which discloses or suggests that telomer acid derivatives would be useful in distillate diesel fuels.
One object of this invention is to provide an additive product which will operate to lower the cloud point and the pour point of hydrocarbon fuels and improve their fillterability.
A further object of the invention is to provide a process for preparing an additive product comprising a heavy metal salt of a branched chain carboxylic acid wherein metallic contaminants such as calcium and sodium are avoided, by reacting the heavy metal oxide and the carboxylic acid, in the presence of a water/immiscible organic solvent system, with a heavy metal sulfate.